The present invention relates to the field of devices and methods for marshalling packaged products, and more particularly to systems for marshalling small packages, such as blister-packaged pharmaceuticals.
Pharmaceutical tablets and pills are often individually packaged in formed plastic “blisters,” which are sealed with a foil backing. In order to expedite the packaging process, blister packets are formed, filled and sealed in multiple laterally-disposed lanes. FIG. 1 is a schematic diagram of a standard blister packaging process, comprising a forming station 101, a feeding station 102, a vision station 103, a sealing station 104, a punching station 105, a transfer station 114 and marshalling station 106.
Blisters are formed out of a continuous web 108 of plastic material at the forming station 101. Blisters are filled with the appropriate quantity of product at the feeding station 102, and the blisters are sealed at the sealing station 104, using a continuous sheet of foil material. The web 108 is controlled by an indexing station 115, which moves stepwise with an established index distance 109. Between the feeding station 102 and the sealing station 104, a vision station 103 determines whether the appropriate quantity of product is present in each packet and whether there is any defective product. At the punching station 105, individual packets 107 are punched out of the continuous formed and sealed web 108. Through the punching station 105 the packets 107 are transferred at the transfer station 114 downstream to the marshalling station 106. The longitudinal centerline of the web 108 establishes the web axis 110. Each of the packets 107 has a longitudinal packet axis 111, which is parallel to the web axis 110.
Individual packets 107 are typically punched out in an in-line array 112 at the punching station 105, as shown in FIG. 1. For convenience, we will refer to them as packets #1, #2, #3 and #4.
At the transfer station 114, defective packets are rejected and only the non-defective packets are transferred in a multi-lane array to the marshalling station 106. The reject verification station 116—comprising an array of photo-sensors connected to the vision station 103 through the machine processor—ensure that all the packets 107 being transferred are in good condition and filled with the right amount of products. If a non-defective packet is rejected or a defective packet is transferred, the reject verification station 116 sends a signal to the processor and the machine automatically stops. In this way, the machine operator can recover the non-defective packet or remove the defective packet from the line.
At the transfer station 114, after defective packets are removed, the in-line array 112 of packets 107 is transferred to a marshaling station 106, where it is rearranged in a pattern amenable to stacking in a shipping container—which is typically a single-file arrangement. In prior art marshalling systems currently in use in the pharmaceutical packaging industry, the multi-lane packet pattern 117 is merged into a single file 118 by converging guide rails 113, as depicted in FIG. 1. This system has the distinct disadvantage, however, that packets—particularly those that are small and lightweight—will often flip over when they contact the guide rail 113 and jam up the marshalling process.
The present invention addresses this problem by providing a “pick & place” marshalling system, which performs the functions of: (a) rejecting empty and defective packets, (b) rearranging the staggered packet array into a single file, and (c) transferring the non-empty, non-defective packets from the indexed conveyor to a single-file marshalling conveyor, which ultimately empties into a shipping container, and (d) making sure that only the non-empty, non-defective packages are transferred and only the empty and defective packages are rejected.